1. Field of the Invention
Exemplary embodiments of the invention relate generally to flat panel displays. More particularly, exemplary embodiments of the invention relate to a method of manufacturing a display substrate and a liquid crystal display (LCD) apparatus using the display substrate.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) panel includes a display substrate, an opposing substrate facing the display substrate, and a liquid crystal layer interposed between the display substrate and the opposing substrate. The display substrate includes a plurality of switching devices for driving pixels. The LCD panel applies a voltage to the liquid crystal layer to control light transmittance in order to display an image.
The display substrate may be manufactured through a five-mask process that includes forming a gate pattern, forming a semiconductor pattern having a semiconductor layer and an ohmic contact pattern, forming a source pattern, forming a contact portion and forming a pixel electrode. Since manufacturing costs for masks are high, a four-mask process and a three-mask process have been developed in order to reduce the number of masks required for manufacturing the display substrate.
When the display substrate is manufactured through a typical three-mask process, the semiconductor pattern and the source pattern are patterned through the same mask, and the contact portion and the pixel electrode are patterned through the same mask. As a result, two masks may be omitted in comparison to the five-mask process.
When the display substrate is manufactured through the typical three-mask process, passivation layers may be excessively etched during photoresist lift off. Thus, the metal layers of the display substrate may be damaged. In order to solve the above-mentioned problems, a method of changing manufacturing conditions, a method of using negative photoresist and a method of structurally changing the contact portion and other such methods have been developed. However, the process margins for the above mentioned lift-off processes may not be sufficient. Therefore, there is a need for a method that enhances the reliability and the process margins for lift-off processes.